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C4478

Sigma-Aldrich

S-Gal®/LB Agar Blend

reagent for selection of recombinant bacterial clones

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NACRES:
NA.85

grade

for molecular biology

Quality Level

200

sterility

non-sterile

form

powder

technique(s)

microbiological culture: suitable

suitability

suitable for β-galactosidase test
nonselective for Escherichia coli
nonselective for coliforms

application(s)

food and beverages
microbiology

storage temp.

room temp

Related Categories

General description

S-Gal® (sodium salt) is an autoclavable, water-soluble, chromogenic substrate for β-galactosidase, used to determine the presence or absence of a cloned DNA insert in bacteria growing on agar plates. S-gal® is designed to replace X-Gal in blue-white selection of recombinant bacterial colonies with the lac+ phenotype.

Application

S-Gal®/LB Agar Blend has been used for the identification of recombinant bacterial colonies.
Suitable for use in selection of recombinant bacterial colonies with the lac+ phenotype. S-Gal® (sodium salt) is water-soluble, autoclavable and can be added to bacterial broth containing agar prior to autoclaving.

Features and Benefits

  • More intense color contrast than X-gal
  • Water-soluble and autoclavable for easiest use
  • Convenient, pre-mixed media

Components

Ingredients (g/L)
Tryptone, 10
Yeast extract, 5
Sodium chloride, 10
Agar, 12
S-Gal, 0.3
Ferric ammonium citrate, 0.5
IPTG, 0.03

Principle

When S-Gal® is cleaved by β-galactosidase, the resulting product will chelate ferric ion to create a black, insoluble precipitate. Lac+ colonies grown in the presence of S-Gal® and ferric ion turn an intense black color, allowing for easy differentiation between lac+ and lac- colonies.

Preparation Note

Suspend contents of one packet in 500 ml distilled or deionized water. Sterilize by autoclaving for 15 to 20 minutes at 121-124°C. For microwaving, heat suspended mix until initial boiling. Mix well. Heat for short intervals with mixing until agar component is in solution. Do not allow boiling for extended periods of time. Antibiotics should be added following autoclaving or microwaving, after cooling to 48-52°C.

Other Notes

The ferric or Fe3+ ion is required for color development and must be added to any S-Gal®
formulation. A medium prepared with S-Gal® is moderately dark due to the presence of ferric ammonium citrate. This darker background often provides enhanced contrast for automated colony counting or isolation.

Legal Information

S-GAL is a registered trademark of Merck KGaA, Darmstadt, Germany

Storage Class Code

11 - Combustible Solids

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Heat shock protein 70 (Hsp70) subtype expression in neuroendocrine tissue and identification of a neuroendocrine tumour-specific Hsp70 truncation.
Zierhut B, et al.
Endocrine-related cancer, 11(2), 377-389 (2004)
Paola Jurado et al.
Molecular microbiology, 60(5), 1218-1227 (2006-05-13)
The identification of single-chain antibodies (scFvs) that interfere in vivo with the building of the complex that activate the prokaryotic, sigma54-dependent promoter Pu of the catabolic TOL plasmid pWW0 is reported. To this end, a phage M13 library of scFvs
LifeScience Quarterly: A superior dye to X-gal for clonal selection.
Heuermann, K. and Cosgrove, J.
Sigma data, 2(2), 2-4 (2001)
John Kelly et al.
Journal of bacteriology, 188(7), 2427-2434 (2006-03-21)
In eukaryotes, N-linked protein glycosylation is a universal modification involving addition of preformed oligosaccharides to select Asn-Xaa-Ser/Thr motifs and influencing multiple biological events. We recently demonstrated that Campylobacter jejuni is the first member of the Bacteria to possess an N-linked
N Martin Young et al.
The Journal of biological chemistry, 277(45), 42530-42539 (2002-08-21)
Mass spectrometry investigations of partially purified Campylobacter jejuni protein PEB3 showed it to be partially modified with an Asn-linked glycan with a mass of 1406 Da and composed of one hexose, five N-acetylhexosamines and a species of mass 228 Da
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